Dental engine.



PATENTE)` APR; 16, 1907. J. A. LEWIS.

DENTAL ENGINE.

.APPLICATION FILED Dnc. 30,1905

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JESSE A. LEWS, OF ELGlN, NEBRASKA.

DENTAL ENGlNE.

Specification of Letters Patent.

Patented April 16, 1907.

Application led December 30, 1905. Serial No. 293,958.

To all whom it may concern.-

Beit known that I, JESSE A. Lnwrs, a citi- Zen of the United States, residing at Elgin, in the county of Antelope and State of Nebraska, have invented new and useful lmprovements in Dental Engines, of which the following is a specification.

This invention relates to dental engines, and has for 'ts object to simplify -the construction thereof, to maintain a steady and regular running of the tool, to insure a prompt response of the tool to the manipulation of the foot-power, and in general to facilitate the handling of the device.

t is proposed to employ frictional gearing for driving the tool, so as to reduce noise to the minimum, and in this connection to provide for the convenient replacing of the friction-surfaces when worn, whereby the engine may be maintained in an effective running order in a very simple and convenient manner.

With these and other objects in view the present invention consists in the combination and arrangement of parts, as will be hereinafter more fully described, shown in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that changes in the form, proportion, size, and minor details may bemade within the scope of the claims without departing from the spirit or sacrificing any of the advantages of the invention. v

In the drawings, Figure 1 is a side elevation of a dental engine embodying the features of the present invention. Fig. 2 is an enlarged fragmentary sectional view showing the frictional drive connection between the foot power and the drive-shaft. Fig. 3 is an enlarged fragmentary sectional view showing the frictional drive connection between the drive-shaft and the counter-shaft. Fig. 4 is an enlarged detail sectional view showing a coupling in the flexible countershaft. Fig. 5 is a sectional view, enlarged, on the line 7 7 of Fig. 1. Fig. 6 is a plan view ofthe supporting-base and the foot-treadle.

Like characters of reference designate corresponding parts in each of the figures of the drawings.

For the support of the present engine there is provided a single base 1, of any approved form, from'which rises a standard 2, which terminates at its upper end in an arched arm 3, overhanging the top of the standard.

That portion of the arm which overhangs the standard is provided with a threaded opening 4, in alinement with a threaded socket 5, in the top of the standard. A tubular casesection 6 is threaded into the opening 4 of the arched arm, and another tubular case-section 7 is threaded into the top of the section 6, as best indicated in Fig. 7 of the drawings.

Within the case-section 6 there is a lower drive-shaft section 8, which projects below the bottom of the case-section 6 and has its lower end mounted in a step-bearing 9, threaded into the socket 5. A suitable bearing 10 is threaded into the lower open end of the case-section 6, so as to maintain the shaft 8 centrally within the case-section 6.

For imparting motion to the drive-shaft a crank-shaft 11 is mounted in the standard 2, with its crank 12 connected by a connecting-rod 13 with the foot-treadle 14, fulcrumed upon the base 1. A suitable spring 15 extends between the treadle and theconnecting-rod 13 to normally maintain the treadle in an elevated position with the crank 12 off of its dead-center. A powerwheel 16 is carried by the crank-shaft 11 and has its beveled rim portion 17 1 working across the space between the top of the standard 2 and the overhanging portion of the arm 3. In this beveled rim there is a pair of annular grooves 18, having` their adjacent walls undercut, so as toproduce an annular dovetailed rib 19. A friction-ring 20, preferably rubber or similar material, is stretched around the annular rib 19 and is provided with opposite inturned elastic iianges 21, sprung into the grooves or channels 18, so as to form a detachable clench connection between the ring and the wheel. By this method of connection extraneous fastenings are dispensed with, and the ring may be convenicntly'replaced when worn or damaged. Upon that portion of the vertical shaft 8 between the top of the standard 2 and the overhang-ing arm 3 is a beveled gear consisting of a body 22, having a hub-23, which is rigidly secured to the shaft by means of pins or other suitable fastenings 24. A beveled friction-disk 25 is suitably secured to the lower face of the gear-body 22-for instance, by screws 26-whereby the frictiondisk may be conveniently replaced when worn. The beveled periphery of the disk 25 is of course in frictional engagement with the ring 2O of the power-wheel 16, whereby IOO IOS

IXO

rotary motion is transferred to the shaft 8 and the noise of intermeshing gears is obviated.

Upon reference to Fig. 7 of the drawings it will be noted that there is an upper driveshaft 27, which is threaded into a threaded seat 28 in the top of the lower shaft-section 8, there being a set-screw 29 to prevent accidental disconnection of the shaft-sections. A shaft-bearing 30, comprising a perforated nut is screwed into the lower end of section 7 of the casing through which is passed the shaft-section 27 to center the latter within the casing. By this assemblage of parts the shaft-sections and case-sections may be taken apart for convenience in transportation and storage.

A plug 3l is threaded into the top of the upper case-section 7 and is provided with a longitudinal bore 32, through which the upper end portion of the shaft-section 27 projects. A yoke-shaped bracket 33 is supported upon the plug 3l, preferably by having the latter threaded through the bottom of the bracket, there being a nut 34 fitted to the upper end of the plug and bearing` against the top of the bracket to rigidly hold the latter upon the plug. Upon the upper projecting end ortion of the shaftsection 27 is a beve ed friction-gear 35, similar in construction to the friction-gear hereinbefore described. The stationary bracket member 33 carries a movable arched bracket member 36, which has one end hinged to one end of the bracket 33, as at 37, so as to overhang the bracket member 33, with the other end of the bracket member 36 overhanging the gear 35 and terminated short of the upper extremity of the shaftsection 27. A substantially horizontal arm 38 is carried by the inner end of the bracket member 36 and is pierced by a threaded plug 39 constituting a thrust-bearing for the upper end of the shaft 27.

The outer end of the arm 38 bears against the upper end of what will be termed the "rear side of the fixed bracket member 33 and carries a pivoted catch 40, provided with a projection 41, which takes into a seat or recess 42 in the bracket member 33, so as to lock the hinged bracket member 36 upon the fixed bracket member. A bowed spring 43 is carried by the arm 38 and bears against the catch 40, so as to hold the latter in its locked position..

The outer upright side of the hinged bracket member 36 is pierced by a countershaft 44, having its rear end mounted in a bearing-socket 45 in the rear side of said bracket, there being a friction-gear 46, carried by the counter-shaft m'thin the bracket member 36 and in frictional engagement with the gear 35. A flexible shaft 56 of suitable length and of any approved construction is connected to the counter-shaft 44 andnormally hangs therefrom in position for convenient access by the operator when manipulating the treadle.

The purpose of the hinged bracket member 36 is to give access to the gears 35 and 46 by swinging said bracket member upwardly upon its pivotal support 37, as will be readily understood by reference to Fig. 3 of the drawings. A projection 48 is provided upon the bracket member 36, and a suitable catch or stop 49 is provided upon the bracket member 33 in position for engagement by the projection 48 when the hinged bracket member is swung upwardly, so as to support the same when applying and removing the gears 35 and 46.

interposed between the flexible shaft-casing sections 47 and 50 is `a detachable connection or coupling, consisting of internallythreaded sleeves 5l and 52, carried by the respective flexible casings of the shaft-sections. A nut 53 is employed to connect the threaded sleeves, and this nut is provided with a longitudinal bore 54, through which passes a rod or stiff shaft-section 55, connected at opposite ends to the fiexible shaftsections 56 and 57. The purpose of the coupling just described is to brace and strengthen the flexible shaft and to center the shaft within the casing. As shown in Figs. l and 2 .of the drawings, it will be noted that handles 76 are provided upon the case-section 6 for convenience in lifting the engine when changing the position thereof.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. ln a dental engine, the combination of `a standard, a yoke-shaped bracket member carried by the top of the standard, a movable bracket member hinged to the stationary member and arching over the top thereof, a detachablecomiection between the bracket members, a drive-shaft carried by the standard and projecting into the space between the bracket members, means for driving said shaft, a gear carried by the drive-shaft and located between the bracket members, a counter-shaft carried by the movable bracket member, and a gear carried by the countershaft and in mesh with the first-mentioned gear. 2. In a dental engine, the combination of a supporting-standard, a tool-driving shaft carried thereby, a friction-gear on said shaft, a drive-gear having undercut retaining-grooves around the rim thereof, a resilient frictionring stretched around the rim and having flanges sprung into said grooves, and means for operating the drive-wheel.

3. In a dental engine, the combination of a standard, a bracket carried by the standard and having a stationary and a hinged portion provided with interlocking means, a driveshaft carried by the standard and projecting IOO into the space between the bracket members, In testimony whereof I ax my signature means for driving said shaft, a gear carried in presence of two Witnesses. by the drive-shaft and located between the bracket members, a counter-shaft carried by JESSE A' LEWIS 5 the movable bracket member, and a gear Witnesses:

carried by said shaft and in mesh With the J. L. AGLER,

first-named gear. ORVEL SHEETS. 

